I had to reinstall APK compiler and all of the android stuff. Tried to follow the documentation, but I got this message when try to compile:"Cannot find Android 2.3 (API 9) developer files in your Android NDK installation!"

These things will of course happen again and again because Google changes the layout of the Android SDK and NDK all the time and APK Compiler needs to be adapted in order to stay compatible with it. I'll fix this for the next version. Until then, use an older SDK/NDK version

I've looked into this now and adapted the APK Compiler accordingly. The downside is that you'll no longer be able to compile for Android versions older than 4.0. This is because Google removed support for Android versions older than 4.0 from the latest NDK. There'll be an update for the APK Compiler soon so that it works with the latest Android Studio again but people who have a working setup should always think twice before upgrading their Android Studio or the APK Compiler because as time goes by, more and more of the support for the old platforms will be removed. There's nothing I can do against this.

- Change: Separate installations of the JDK and Gradle are no longer necessary; the APK Compiler uses the JDK and Gradle that is shipped with Android Studio now- Fix: Fixed the APK Compiler for Android Studio 3.0.0; since the NDK r16 doesn't support older versions than Android 4.0 any longer, APKs compiled by the APK Compiler also require at least Android 4.0 now